ci: add ruby-3.3

Author: yoshoku

.github/workflows/build.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ '3.0', '3.1', '3.2' ]
+        ruby: [ '3.0', '3.1', '3.2', '3.3' ]
     steps:
       - uses: actions/checkout@v4
       - name: Set upt Ruby ${{ matrix.ruby }}